Primus 703

I've just bought a nice example of this furnace however it's minus it's burner tube. Does anyone know the dimensions ie diameter height and thickness and also whether it was originally cast or tube steel as I'd like to get one made as no doubt a replacement can no longer be sourced
Hope some has the answer.

 

The catalogue illustrations definitely seem to show steel tubing - e.g. here. No dimensions however, but you might find it worth taking the burner down to your local scrapyard and seeing if you can find a piece of old exhaust pipe of the right diameter to fit. Get a decent length to have sufficient for a little bit trial and error with the height. I can't be the only one who has had success with this method for fabricating tubes for odd size rocket burners

 

Thanks Ian
As chance would have it my vans in for its MOT at the weekend and the garage is an exhaust centre. You reckon steel tube rather than cast ie an old manifold or should i try both .

 

@glassmanallan

Exhaust pipe is excellent:


https://classiccampstoves.com/threads/sievert-no-3099.35515/

https://classiccampstoves.com/threads/sievert-no-3099.35515/

Tony

 

Many thanks.steel tube rather than cast manifold seems to be the order of the day

 

Cough Cough...... HERE
A useful and inexpensive source of tubing

Alec.

 

You guys all seem to sing off the same hymn sheet. Exhaust tube hunt here I come

 

At least on my Primus & Optimus rocket stoves have flame tubes made of steel. Right diameter steel, brass or SS tubes should work fine. Copper & coated(zinc/etc.) tubes might cause discoloration to flames.

Basecamp seems to have some flame tubes available as spare part(please check that size is correct!):

https://www.base-camp.co.uk/Optimus.html

P5188 Flame tube for 'Rocket stove, 732 to 735 & 741 to 747 £ 6.90

 

I'll check that out . Thanks

 

Brass tubes work fine on a 'rocket' stove.

 

Another thing that would work and perhaps cosmetically might look better

 

The Primus No 703 furnace needs a larger flame tube then the multi-burner rocket stoves.

On the Fogas website it is mentioned the 703 is equivalent to the Optimus No 528: http://www.fogas.se/shop/5137---laagformsroer-gjutjaern/
The inner diameter of the flame tube of a No 528 is 62mm according to this catalogue: https://classiccampstoves.com/attachments/optimus_1600_81-jpg.189755/

The orginal flame tubes of these furnaces are made of thick steel (maybe it's cast iron, don't know for sure) or at least the original burner tube of my Optimus No 529 has a steel flame tube (inner diameter = 72mm)

The Optimus 507-516 and Primus 732-735 & 741-747 use a 40mm flame tube.

 

To sit as snug as possible i think the outer diam is 68.mmm. just a case of guestimating the overall length it should be.perhals anyo e with a furnace type burner could say how far theirs extends past the top of the burner

 

The multi-burner furnace/heater type of stove do use brass tubing.
However, if the burner is very big, then cast iron burner tubes/flame spreaders are used.

Here is my Monitor 'Big Burner' with a cast iron tube/flame spreader.

 

@shagratork , Trevor,

I remember seeing your pin-up girl on this big Monitor before, and I still love seeing her in action!! Well done, my friend!! Fun! Take care, and God Bless!

Doc